Roger Federer‘s dominance over the US Open has faded in recent years and his one-sided record against Stan Wawrinka has become more of a battle. Will Federer turn back the block in Friday’s semifinals and beat Wawrinka to return to the US Open final? Forget Swiss neutrality: Friday night in New York is all about Swiss brutality as Roger Federer and Stan Wawrinka leave friendship at the entrance to the court and battle for a place in the US Open final. Roger Federer and Stan Wawrinka will clash for the 20th time in the semi-finals of the US Open on Friday.

It’s remarkable, given the supremacy Federer had once established over the fourth and final Grand Slam of the year, that the five-time US Open champion hasn’t reached the US Open final since 2009, when he lost in five sets to Juan Martin del Potro. Denied by Novak Djokovic in the semifinals in 2010 and 2011, Federer made two relatively early exits by his standards in 2012 and 2013, and when he returned to the semifinals in 2014, he was defeated by an inspired Marin Cilic, who blasted him off the court in straight sets. In fact, you have to go back to 2011 to find the last time Federer made a Grand Slam final at any tournament outside of Wimbledon, and the 2010 Australian Open for the last time he made a hard-court Slam final. These facts are not insignificant.

There’s a kind of poetry in the fact that Federer faces Stan Wawrinka, whose career blossomed late after so many years in his compatriot’s shadow, in Friday’s semifinals. Wawrinka’s Grand Slam record compared to Federer’s is as lopsided as their head-to-head – 16-3 in Federer’s favour – but both have shifted dramatically in recent years. Don’t let this one deceive you. Roger Federer may have won 13 of their 14 earliest meetings, but late-blooming Stan Wawrinka was, for a long time, the guy with all the talent, without the consistency, and without belief and confidence. Federer also leads 11-0 on hard-courts.

Since winning his first major at the 2014 Australian Open, Wawrinka has won two of his five duels with Federer – and in the match that puts Roger 3-2 ahead, Stan had four match points. He also won their last encounter, a straight-sets heart-breaker that kicked the No. 1 Swiss out of the French Open – which the Swiss no. 2 would go on to win. Between 2009 and 2014, Federer went undefeated against Wawrinka, as he defeated his lower ranked compatriot eleven times in a row.

All three of Wawrinka’s victories against Federer have come on clay courts, often in slow, damp conditions. Federer on a quicker Arthur Ashe Stadium will be an entirely different proposition – especially given the way that the second seed has been playing. Federer came into the US Open on the back of a victory at the Cincinnati Masters and is the only player still alive in the draw not to have dropped a set (Wawrinka has lost just one, to Donald Young).

Both players have really been crushing all opposition so far at the US Open, with Wawrinka even imitating Federer’s new aggressive returning technique – SABR, or Sneak Attack Behind Return – in his last match against Kevin Anderson. Federer has been playing at a higher level, with Wawrinka more just getting through his matches before raising his level somewhat in his last two matches, but that could mean the fifth seed is peaking at the right time – and that Federer could be unprepared for his first serious opposition, something we’ve seen with him at Grand Slams recently where he cruises until it matters.

We know how Federer is going to play: He’s going to play the same super-attacking tennis which has got him to this point. And we know how Wawrinka will have to play; big, big on every shot, to try to dominate and take the initiative from the first ball. He did it superbly in the quarterfinals of the French Open, but it will be much more difficult for him in New York. The match-up looks far too close to be settled in straight sets but Federer is much more comfortable with the kind of tennis he’s going to need to play than Wawrinka is and, if the five-time US Open champion can manage his nerves, that might be what sees him into his first US Open final for six years.

Roger is possibly playing his best tennis since the 2012 Wimbledon triumph but Stan’s late career rise is definitely note-worthy winning 2 slams. Roger will hold off his compatriot in this epic. The big question for Stan is can he turn up? Roger is  not expected to miss his best chance to win Grand Slam No.18. One thing is for sure – we will have a Swiss man in the finals on Sunday